PROJECT SUMMARY/ABSTRACT One of the most common reasons for the replacement of dental restorations is recurrent (secondary) caries at the gingival tooth-restoration interface. Human salivary enzymes such as esterases hydrolyze dental resins to produce biodegradation products. A two-fold approach is proposed wherein: 1] the degradation of composite and adhesive resins will be characterized after long-term salivary esterase exposure, and 2] the impact of long-term salivary esterase exposure on biofilm structure and growth will be characterized. This proposal offers a novel in vitro approach that correlates surface degradation of resins with oral biofilm formation under clinically relevant conditions. The methodology proposed will be beneficial for the testing of future resin composite and adhesive resin formulations, and could easily be adapted to assess biodegradation in other types of biofilms. The proposed project will benefit dental and dental hygiene students by exposing them to research, and will strengthen the research environment of an educational institution that has not been a major recipient of NIH funds, which are the goals of the R15 (AREA) award.